title: Modeling phosphate transport and removal in a compact bed filled with a mineral-based sorbent for domestic wastewater treatment.
abstract: Phosphorus filter units containing mineral-based sorbents with a high phosphate (PO4) binding capacity have been shown to be appropriate for removing PO4 in the treatment of domestic wastewater in on-site facilities. However, a better understanding of their PO4 removal mechanisms, and reactions that could lead to the formation of PO4 compounds, is required to evaluate the potential utility of candidate sorbents. Models based on data obtained from laboratory-scale experiments with columns of selected materials can be valuable for acquiring such understanding. Thus, in this study the transport and removal of PO4 in experiments with a laboratory-scale column filled with a commercial silicate-based sorbent were modeled, using the hydro-geochemical transport code PHREEQC. The resulting models, that incorporated the dissolution of calcite, kinetic constrains for the dissolution of calcium oxide (CaO) and wollastonite (CaSiO3), and the precipitation of amorphous tricalcium phosphate, Ca3(PO4)2, successfully simulated the removal of PO4 observed in the experiments.
authors.affiliation: Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, 971 87 Luleå, Sweden.
authors.forename: Inga
authors.initials: I
authors.lastname: Herrmann
authors.forename: Amir
authors.initials: A
authors.lastname: Jourak
authors.forename: Jon Petter
authors.initials: JP
authors.lastname: Gustafsson
authors.forename: Annelie
authors.initials: A
authors.lastname: Hedström
authors.forename: T Staffan
authors.initials: TS
authors.lastname: Lundström
authors.forename: Maria
authors.initials: M
authors.lastname: Viklander
mesh_terms: D000327:Adsorption; D002119:Calcium Carbonate / Q000737:chemistry; D017610:Calcium Compounds / Q000737:chemistry; D005374:Filtration; D008962:Models, Theoretical; D010087:Oxides / Q000737:chemistry; D010710:Phosphates / Q000737:chemistry*; D017640:Silicates / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D014865:Waste Disposal, Fluid; D062065:Wastewater / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D002119:Calcium Carbonate; D017610:Calcium Compounds; D010087:Oxides; D010710:Phosphates; D017640:Silicates; D012822:Silicon Dioxide; D062065:Wastewater; D014874:Water Pollutants, Chemical; C016538:lime; C031293:calcium silicate
keywords: Constructed wetlands; Filtration; On-site wastewater treatment; PHREEQC; Phosphorus; Reactive transport modeling